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Biodiesel (methyl ester) was synthesized from cottonseed oil (CSO) with methanol in the presence of an alkali catalyst (KOH) through the transesterification method. Response surface methodology (RSM) optimized the methyl ester synthesis process. The experimental design matrix was arranged using the Box-Behnken Design (BBD) of RSM. The optimization of methyl ester was achieved by varying variables such as the methanol to CSO ratio, the concentration of the catalyst, and the reaction duration. A contour plot and a surface plot were generated to illustrate the impact of these variables on methyl ester synthesis. The biodiesel yield was modeled as a quadratic equation through RSM analysis, with a coefficient of determination (R2) and adjusted R2 of 0.97 and 0.968, respectively. The optimized CSOME yield (95.04%) was numerically gained at a 1:6 methanol to CSO ratio, a reaction duration of 52.2 min, and a 0.985 wt% catalyst concentration. Based on these parameters, a 94.80% CSOME yield was experimentally obtained. This shows that response surface methodology (RSM) is sufficient for optimizing methyl ester yield. The produced methyl ester was characterized to determine its physicochemical properties. Gas chromatography-mass spectrometry (GC-MS) analysis was used to identify the specific type and proportion of fatty acid esters present in the CSOME. The main types of fatty acids found in CSOME were methyl 9-cis 11-trans-octadecadienoate (C18:2), hexadecanoic acid methyl ester (C16:0), 11, 14-octadecadienoic acid methyl ester (C18:2), methyl 8, 9-octadecadienoate methyl ester (C18:2), and myristic acid methyl ester (C14:0).

Terminal drought and lodging are among the major yield-limiting factors for tef cultivation in the highly weathered soils of the Ethiopian highlands. Therefore, a study was conducted to assess the yield and lodging responses of tef to varying moisture depletion levels (MDL) and the application of carbonized rice husk (CRH). A two-year 4×4 factorial experiment with 20, 35, 55, and 75% MDL and 0, 291, 582, and 873 kg ha-1 of CRH was laid out in a split-plot design, with each treatment replicated four times. The pooled mean ANOVA showed leaf area index (LAI) and lodging index (LI) were not significantly influenced by the main and interaction effects of MDL and CRH (p > 0.05); however, individual year ANOVA showed that both LI and LAI were influenced by the interaction of MDL and CRH (p

Even though CI engines are more efficient than SI engines due to their ability to operate at a greater compression ratio, a leaner charge, and lower throttle losses, they have higher PM and nitrogen oxide emissions. The induction system modification with fuel port injection is used as a parameter in RCCI engine operations for controlling emission through in-cylinder charge reactivity and combustion phasing. By varying the amount of hydrous bioethanol in the premixed fuel injection ratio, the engine’s performance and emissions are greatly affected. In this study, an experimental investigation of a triple-fuel RCCI engine running on port-injected gasoline-bioethanol blend and direct-injected diesel fuel was conducted. Taguchi’s experimental design method was employed to assess the impact of various independent variables utilizing three set levels and two factors with the L9 orthogonal array. From the findings, the delta value shows the highest average response for each factor. Engine speed has the largest effect on the signal-to-noise ratio (SNR) with the (delta value of: 10.7446, rank = 1), and the delta value of 38.96, rank = 1, has the largest effect on the response of means at engine speeds of 3000 rpm. The premixed fuel ratio of G25BE75 (delta: 87.30, rank = 1) has the largest effect on the standard deviation. The lines are not parallel in all emission and performance cases except for Tb and CO2, which are close to parallel. The best means in engine speed and premixed blended fuel ratio were NOx, CO, HC, and brake power. At 3000 rpm, the speed had the larger main effect plots of SNR. The premixed fuel ratio of G25BE75 had higher main effect plots for means and standard deviations. The residues appear to have been dispersed normally based on a straight line by using a normal probability plot. The data are normally distributed, as demonstrated by the normal probability plot, and the factors had an impact on the response. Conferring to the experiment result, a high engine speed and higher ethanol content in the RCCI premixed fuel are preferred for reducing nitrogen oxides (NOx) and carbon dioxide (CO2), while unburned hydrocarbons (UHCs) and carbon monoxide (CO) showed a slight increase.

Lodging, poor crop varieties and nitrogen management are among the main tef cultivation problems in acidic soils of northwestern Ethiopia. Though Si has been shown to improve crop yield and lodging resistance, knowledge of its effect on tef, along genotypes and nitrogen, is yet to be uncovered. Therefore, a 4 × 2 × 2 factorial field experiment was conducted on fixed experimental plot at the Koga irrigation scheme to assess yield and lodging responses of tef varieties to nitrogen and silicon fertilizer rates during two consecutive years of 2021 and 2022. The experiment comprised four nitrogen levels: 0 (N1), 23 (N2), 46 (N3), and 92 kg N ha−1(N4), two Si levels: 0 (Si1) and 485 (Si2) kg ha−1, and two improved varieties: Hiber-1 (V1) and Quncho (V2) treatment combinations, which were replicated four times. Results showed that regardless of silicon supply and variety, nitrogen had a significant effect (p < .0001) on agronomic attributes of tef grain yield, biomass yield, harvest index, chlorophyll content, plant height, panicle length, leaf area index, and the number of plants m−2 over the two years. Application of N4, N3, and N2 improved grain yield by 166.9, 126.2, and 75.2 % over N1, respectively. The harvest index showed a declining trend with nitrogen rates, which ranged from 36.1 to 26.5 %. Hiber-1 showed a significantly (p < .01) higher panicle length than Quncho. The interaction of nitrogen, silicon, and variety significantly (p < .001) affected lodging index, with a minimum lodging index of 0 % from V1Si1N1 and a maximum lodging index (71.9 %) from V2Si1N4. Maximum net return (2552.6 USD) was obtained from V1Si1N4, while the marginal rate of return (6961.7 %) from V1Si1N3. Therefore, it can be concluded that genotype and optimum nitrogen can maximize yield and lodging resistance of tef, while silicon in the form of carbonized rice husk results no significant effect on tef lodging.

To satisfy customers, the quality of watermelon should not deteriorate throughout the value chain. Hence, this study aimed to evaluate the effects of storage alternative (plastic shade, zero energy cool chamber, naturally ventilated onion storage, and ordinary storage room), storage duration (1 st, 2nd, 3rd 4 th, and 5th -weeks), and variety (Crimson-sweet and Sugar-baby) sampled from three locations with factorial combinations in completely randomized design (CRD) with three replications. Storage condition, duration, variety, and location influenced the quality attributes. The plastic shade and ordinary storage room maintained better TSS (total soluble solids) compared to the others. Crimson-sweet maintained better TSS, acidity content, and overall acceptability during storage. Regardless of storage conditions, variety, and location, TSS decreased while pH increased with prolonged duration. TSS below the US standard of 8% manifested after the 4th -week of storage. The ordinary storage room maintained sensory qualities the best. The overall acceptability of stored fruits was ‘neither like nor dislike’ according to the panelists after the 4th -week in all storage conditions. It is concluded that watermelon has a shelf-life of one month. Therefore, we recommend plastic shade and ordinary storage room, Crimson-sweet variety, and Ribb and Woramit locations, for the watermelon value chain in Ethiopia.

A two-year field experiment was carried out to scrutinize the integrated use of NPSZnB blended fertilizer and farmyard manure (FYM) on maize growth and yield components at Koga and Bachima villages in Mecha district and Geray and Jiga villages in Jabi Tehran district. Factorial combinations have five levels of NPSZnB (100, 150, 200, 250, and 300 kg·ha−1), and four rates of FYM (0, 12, 16, and 20 t·ha−1), plus one blanket recommendation (200 kg·ha−1 DAP and 150 kg·ha−1 Urea). A randomized complete block design with three replications was used to set up the studies. Except for days to silking and leaf area index at both locations, and days to physiological maturity, and ear length at Mecha, main and interaction effects on all parameters were detected at both locations. The only main effect of NPSZnB was detected on the harvest index at Jabi Tehnan. Generally, the results achieved from the interaction effect were better and greater than those obtained from the blanket recommendation although this was not the case for the main effects. Grain yields at Jabi Tehnan and Mecha were 5618.5 and 5421 kg·ha−1, respectively, as a result of the unified use of 250 kg·ha−1 NPSZnB and 20 t·ha−1 FYM and shortened days to 50% tasselling by 3.46 days and delayed 90% physiological maturity by 2.95 days than the blanket recommended fertilizer at Jabi Tehnan. As the main effect, compared to the blanket recommendation, 250 kg·ha−1 at Jabi Tehnan and 300 kg·ha−1 NPSZnB at Mecha reduced the days to 50% silking by 0.225 and 0.292 days, respectively. Contrasted with the conventional recommendation, the application of 300 kg·ha−1 NPSZnB minimizes days to 90% physiological maturity by 0.89 at Mecha, and the rise in FYM level from 0 to 20 t·ha−1 caused 0.832 and 0.279 extra days to reach 50% silking at Jabi Tehnan and Mecha, respectively. The yield had a very strong correlation that is positive with growth and yield components. Economic study: the use of 200 kg·ha−1 NPSZnB with 20 t·ha−1 FYM resulted in the maximum net benefit of 36221.06 and 35431.04 ETB ha−1 at Jabi Tehnan and Mecha, respectively. Thus, 250 kg·ha−1 NPSZnB with 20 kg·ha−1 FYM and 200 kg·ha−1 NPSZnB with no FYM application were the most acceptable rates at both locations with a low cost of production to small-scale farmers. For resource-rich farmers, 200 kg·ha−1 NPSZnB with 20 t·ha−1 FYM was also favorable, with the best net benefit at both locations.

AbstractIntercropping of cereals and legumes is common in Ethiopia. However, intercropping of lupine with tef is a new practice in Northwestern Ethiopia’s tef-based cropping system. In the 2016 and 2017 main cropping seasons, a field experiment was conducted in Gozamin District, East Gojjam Zone, to assess the effect of plant density of lupine intercropping with tef on the productivity of tef fields. The two experimental factors were two inter-row spacings (20 and 40 cm) and three intra-row spacings (10, 15, and 20 cm) of lupine intercropped with tef, and their factorial combination was studied using a randomized complete block design (RCBD) with three replications. The highest tef grain yield (1.80 t ha−1) was recorded from 40 and 20 cm inter- and intra-row spacing of lupine intercropped with tef, respectively. The highest lupine yield (2.74 t ha−1) was recorded from sole cropping. A total of 40 and 15 cm inter- and intra-row spacing of lupine intercropped with tef improved tef equivalent yield (2.32 t ha−1), area time equivalent ratio (1.09), actual yield loss (0.87), monetary advantage index (396.2 USD), net benefit (2479.5 USD ha−1), and marginal rate of return (MRR) (682%). Among all planting densities, 40 and 15 cm inter- and intra-row spacing of lupine were the most profitable and had the highest yield advantage based on equivalent yield and other economic benefits. To maximize the productivity of tef fields, 40 cm of inter- and 15 cm of intra-row spacing of lupine intercropping with tef was recommended.

Diesel engines are widely used due to their higher thermal efficiency and lower Hydrocarbon (HC) emissions. The price fluctuation of petroleum fuel; the none-renewability and different hazardous emissions from petro-diesel, researchers are searching for a suitable renewable energy source for diesel engine. Ethanol is one of the promising alternative fuels that could be used to power diesel engine. Some of the techniques so far tried are ethanol fumigation, dual injection and blending. The former techniques need different engine modification to enable the additional systems to work on the existing engines. Blending is the best technique to substitute the existing diesel fuel as long as we prepare it as per the current diesel fuel minimum requirement. For this specific case micro emulsion of ethanol in diesel fuel with emulsifier is prepared by using magnetic stirrer and bath type ultrasonicator. Nickel Zinc Iron Oxide (NiZnFe2O4) nanoparticle is added in one of the selected emulsion which is having 10% ethanol in three different dose as additive to see the effect on the performance and emission variation of the emulsion compared with diesel fuel. The performance of the prepared sample fuels are tested on a test rig with single cylinder diesel engine. The emission is measured by using exhaust gas analyzer and smoke opacity meter. The specific fuel consumption, brake torque and brake power of E5 (95% diesel and 5% ethanol), E10 (90% diesel and 10% ethanol) and E15 (85% diesel and 15% ethanol) are evaluated and the result showed 27, 34 and 37% increment in fuel consumption; 15, 5 and 15% reduction in brake torque and the power reduction is 19, 7 and 12% respectively. E10 is selected for further test with addition of the nanoparticle with 25, 50 and 100ppm named as E103N25 (E10 with 25ppm NiZnFe2O4 nanoparticle), E103N50 (E10 with 50ppm NiZnFe2O4 nanoparticle) and E102N100 (E10 with 100 ppm NiZnFe2O4 nanoparticle). The result showed fuel consumption reduction by 16, 27 and 27% torque output increment of 1, 2 and 2% and power output increment of 5, 7 and 7% respectively compared with E10. The emission result revealed that the HC emission reduced by 50, 58 and 71% for E103N25, E103N50 and E103N100 fuel samples respectively, Carbon monoxide (CO) emission reduced by 67, 80 and 81% for E103N25, E103N50 and E103N100 fuel samples respectively. The reduction in smoke emission is reduced by 60, 69 and 61% for E103N25, E103N50 and E103N100 fuel samples respectively. Nitrogen oxide (NOX) and Carbon dioxide (CO2) emissions increased with the amount of nanoparticle added in to the fuel.

In developing countries like Ethiopia, where the time of harvesting coincides with the dry season, farmers cure onion bulbs naturally on the field. Field curing generally takes longer than artificial curing and results in more losses and reduced quality of the bulbs due to increased risks for infestations and uncontrolled suboptimal drying conditions. Large-scale artificial curing systems are expensive and electrical energy supply is limited in rural areas. A CFD model was employed to design an alternative and sustainable onion curing system that can be deployed on the field in rural areas. The developed CFD model was validated by comparing the predicted air velocity, temperature, and mass loss to measured values on a prototype curing system operated on a field in Ethiopia. A good agreement between the model and experimental value was observed for the time profiles of temperature at different positions in the bulk of onions during curing, expressed by a root mean square error of 1.1°C in the temperature range from 28 to 47°C, 0.16 m s−1 in the velocity range from 0.1 to 2.5 m s−1, and 0.565% for the mass loss that ranged up to 6.35%. The developed model was used to assess the air velocity, temperature, and relative humidity distribution in order to get an insight into the uniformity of curing of onion bulbs using the develop alternative curing system. For all of the examined curing durations, the drying air temperature variation inside 80% of the porous medium was < 3°C. In the remaining 20% of the porous medium, a temperature variation of up to 6°C was observed. Thus, the newly designed and developed curing system was found to cure the onion bulbs uniformly. Moreover, its performance was evaluated experimentally and the onions were cured to a desirable level of curing for long-term storage within a total curing duration of 48 h. It is vital to consider bulb shrinkage, particularly in the neck, in order to further improve the model mass loss prediction.

Searching for ultra-low emission engines particularly for automotive applications is still ongoing. Even though LTC combustion mode results a prominent advantages in terms of reducing both NOx and PM and also lowering the consumption of fuel, it mainly faces with the challenge of excess emissions of HC and CO. This study aimed to optimize the operating control factors for low emissions in PCCI-DI engine under LTC mode. Parameters include injection timing, EGR level, dieseline ratio and engine load. Computation of analyzing the grey relation with hybrid of Taguchi was applied. In designing of experiments and conducting tests Taguchi's L9 matrix was applied. Air-blast of methanol intake port supply and dieseline application instead of diesel was implemented aiming emission reductions. Optimum combinations were found using GRA and ANOVA. Following the optimization work; advanced injection timing of 25o before TDC, 25% EGR, dieseline 90:10 in % and load 75 % (A2B1C3D3) was found optimal combination level for the proposed aim of emission reductions. Key findings of the results following the experiment conducted using this optimal combination includes; reduction of 68.02% NOx and 62.37% in smoke comparing with the base-line conventional diesel combustion mode. Rankings and ANOVA indicated another findings that injection timing being most influential with a contribution of 69.35% followed by load, dieseline ratio and EGR level respectively. This study confirmed dieseline direct injection with methanol port injection is capable of reducing emissions and better NOx with HC and CO trade-offs in PCCI-DI engines.

The main objective of this work is to analyse the impact of different EGR configurations (no EGR, cold EGR, and hot EGR) on exhaust emissions of PCCI-DI engine. Methanol port injection, dieseline direct injection, advanced injection timing, and different EGR rates were adapted and optimized on the baseline engine. A hybrid algorithm of grey relational analysis with the Taguchi method was implemented for optimization. Results were compared among the PCCI-DI combustion strategy with the baseline using cold EGR, hot EGR, and no EGR configurations. Both cold and hot EGR configurations resulted in lower emission of NOx plus smoke at different loads. At low loads, hot EGR showed promising results of lower HC and CO than the cold EGR with a difference of 18.33% and 33.3%, respectively. NOx and smoke reductions simultaneously and better trade-offs were obtained using cold EGR configuration.

The application of optimal fertilizer rates for component crops improves productivity, land use efficiency, and profitability in an intercropping system. Two field experiments during the 2019 and 2020 cropping seasons were conducted in Adet and Debre Tabor districts with the objective of evaluating the nutrient requirements of sweet lupine in bread wheat-sweet lupine under additive design intercropping systems. Sweet lupine grown in bread wheat-sweet lupine intercropping was fertilized with seven fertilizer levels (0%, 25%, 50%, 75%, 100%, 125%, and 150% of the blanket-recommended NP fertilizer rate of sole lupine) and laid out in a randomized complete block design with three replications. The findings revealed that the highest grain yield of sweet lupine in wheat-sweet lupine intercropping system at Adet was achieved at 125% NP (0.51 t·ha−1) and 150% NP (0.52 t·ha−1), followed by 100% NP (0.43 t·ha−1) and 50% NP (0.35 t·ha−1) fertilizer levels of sweet lupine. Similarly, the highest grain yield of sweet lupine in Debre Tabor was recorded by the application of 125% NP (2.07 t ha−1) fertilizer level of sweet lupine followed by 150% NP (1.89 t·ha−1), 100% NP (1.71 t·ha−1), and 50% NP (1.70 t·ha−1) fertilizer levels. For every invested Ethiopian Birr in the treatments of 50% and 125% NP fertilizer levels of sweet lupine averaged additional profits of ETB 7.667 and ETB 4.537, respectively, can be obtained from sweet lupine that grew under bread wheat-sweet lupine intercropping system. Based on the averaged MRR across the different cost price ratio, application of 50% NP fertilizer level of sweet lupine can be recommended for profitable production of sweet lupine in bread wheat-sweet lupine under additive design intercropping system in Adet and Debre Tabor and areas with similar agroecology as it recorded the highest net return with acceptable marginal rate of return.

Agronomic strategies such as choosing the optimal row ratio and planting legume crops at the right time are crucial for enhancing crop productivity. A field experiment was conducted in 2016 and 2017 to assess the influence of plant density and lupine intercropping time on tef field productivity. The treatments were as follows: tef was planted at a 20 cm inter-row spacing, lupine was sown at 20 and 40 cm inter-row spacing (row ratio of 1 tef: 1 lupine and 2 tef: 1 lupine) and lupine intercropped three times (1, 2, and 3 weeks after tef planting). Randomized complete block design (RCBD) with 3 replications were used. Two sole tef and lupine were planted. The results revealed 40 cm inter-row spacing and delayed lupine intercropping (3 weeks after tef planting) provided the maximum tef grain yield of 1.80 t ha−1. The sole cropping of lupine produced the highest lupine grain yield (2.63 t ha−1). Lupine intercropping at 40 cm inter-row spacing and two weeks after tef planting resulted in the highest land equivalent ratio (1.54), tef equivalent yield (2.45 t ha−1), area time equivalent ratio (1.11), system productivity index (2.5), monetary advantage index (15206 birr ha−1), net benefit (65109 birr ha−1), and marginal rate of return (602%). Therefore, farmers in the northwest Ethiopian highlands should consider intercropping lupine two weeks after tef planting in-between two rows of tef as an effective intercropping system.

The utilization of nanoparticle in ethanol-diesel emulsions combustion catalyst is important. For this study, ethanol and diesel fuels are emulsified varying the ethanol amount as 5, 10, and 15% volume ratio designated as E5, E10, and E15, respectively, by using span 80 and tween 80 emulsifying agents. Nickel Zinc Iron Oxide (NiZnFe2O4) nanoparticle is used in each fuel sample with a dose rate of 25, 50, and 100 ppm. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant is used to keep the nanoparticle homogeneously suspended in the fuel. Mechanical steering and ultrasonic vibrator are used to prepare the sample fuel. A single-cylinder diesel engine testing rig is used to test the performance. For the ethanol-diesel emulsion, the power and torque output decreased as the ethanol percentage and the BSFC increased. The nanoparticle addition improved power and torque output and reduced BSFC. Ethanol-diesel emulsion fuel performance characteristics could be improved with the utilization of NiZnFe2O4.

Tropical highland environments present substantial challenges for climate projections due to sparse observations, significant local heterogeneity and inconsistent performance of global climate models (GCMs). Moreover, these areas are often densely populated, with agriculture‐based livelihoods sensitive to transient climate extremes not always included in available climate projections. In this context, we present an analysis of observed and projected trends in temperature and precipitation extremes across agroecosystems (AESs) in the northwest Ethiopian Highlands, to provide more relevant information for adaptation. Limited observational networks are supplemented with a satellite‐station hybrid product, and trends are calculated locally and summarized at the adaptation‐relevant unit of the AES. Projections are then presented from GCM realizations with divergent climate projections, and results are interpreted in the context of agricultural climate sensitivities. Trends in temperature extremes (1981–2016) are typically consistent across sites and AES, but with different implications for agricultural activities in the other AES. Trends in temperature extremes from GCM projected data also generally have the same sign as the observed trends. For precipitation extremes, there is greater site‐to‐site variability. Summarized by AES, however, there is a clear tendency towards reduced precipitation, associated with decreases in wet extremes and a tendency towards temporally clustered wet and dry days. Over the retrospective analysis period, neither of the two analysed GCMs captures these trends. Future projections from both GCMs include significant wetting and an increase in precipitation extremes across AES. However, given the lack of agreement between GCMs and observations with respect to trends in recent decades, the reliability of these projections is questionable. The present study is consistent with the "East Africa Paradox" that observations show drying in summer season rainfall while GCMs project wetting. This has an expression in summertime Ethiopian rain that has not received significant attention in previous studies. [ABSTRACT FROM AUTHOR]

Recycled engine oil was produced from used engine oil (15W-40) using a combination of MEK and 1-butanol solvents with an activated carbon adsorbent through the adsorption process. The experimental design matrix was prepared using Box-Behnken design (BBD) package within RSM, and recycled engine oil is optimized by response surface methodology (RSM). By varying solvent-to-oil ratio, the temperature and contact duration optimal conditions were identified as a 5.5:1 MEK and 1-butanol solvent-to-oil ratio, 50 min of contact, 42.5 °C, and constant 1 g of activated carbon adsorbent, yielding (65.20%, 65.20%) numerically and experimentally, respectively. Process factors (solvent-to-oil ratio, the temperature, and contact duration) influencing the yield of recycled engine oil are indicated by both contour and surface plots. The characterization of recycled oil indicates that its physiochemical properties, such as density, viscosity, flash point, pour point, and total base number, met the ASTM standards. GC-MS analysis further identified the presence of natural base oil, additives (polymeric, metallic, and non-metallic), and oxidation compounds, indicating the efficacy of the recycling process in recovering valuable components from the used engine oil. Before and after adsorption, FTIR is used to analysis the effect of optimized engine oil adsorption on the activated carbon adsorbent. The recycling method that has been optimized indicates potential for sustainable resource consumption and conservation, which may help the vehicle industry practice environmental stewardship., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)